Abrasive tool



March l, 1949. G, w, ALLRED. 2,463,234

ABRAS IVE TOOL Filed May 21, 1947 Patented Mar. 1, 1949 UNITED STATES ATENT OFFICE ABRASIVE TOOL George W. Allred, Mayodan, N. C. Application Mayl 21, 1947, Serial No. 749,497

8 Claims. l

This inventionl relates to an abrasive tool comprising sandpaper, emery paper, emery cloth or the like, 1 e. any suitable iieXible support such as paper or cloth provided with an adhesively attached coating of abrasive grains or powder such as sand, emery or the like.

The invention resides primarily in an abrasive strip which may be used as such in pieces of any desired size or in the form of a continuous belt having one or a plurality of layers, or in the form of a, pad, or in the form of a wheel or drum. The abrasive strip consists essentially of the abrasive and its adhesively attached flexible support which for convenience will be referred to hereinafter as sandpaper, and means for adhesively attaching successive layers of the strip to each other Without applying the adhesive to the abrasive surface.

An object of the invention is to provide an adhesive strip construction which, when wound around a rotatable shaft to form a wheel and rotated as is customary in the use of abrasive wheels, will be flexible or soft to the object being sanded due to the expansion centrifugal force.

A further object of the invention is to provide an abrasive strip construction which readily can be varied by simple adjustment of the tape folding mechanism in which the strip is formed so as to produce-a strip that when wound to form a wheel will give a wheel of any desired degree of softness.

Other objects and advantages of the invention will appear in the following detailed description of the several illustrative-embodiments shown in the accompanying drawings in which Fig. 1V is a front elevation of a sandpaper wheel,

Fig. 2 is a greatly enlarged cross-section of several layers of the abrasive strip illustrating a relatively hard strip construction,

Fig. 3 is a greatly enlarged cross-section of several layers of a strip construction similar in every respect to that illustrated in Fig. 2 excepting' that it is a relatively soft construction and appears expanded aswhen subjected to centrifugal force in a rotating wheel,

Fig. 4 is a greatly enlarged cross-section showing the elfect'of the pressure of the article being sanded upon the construction illustrated in Fig. 3,

Fig. 5 is vagreatly enlarged cross-section showing several layers of a modiiied strip construction,

Fig. 6 is a greatly enlarged cross-section showing several layers of another modied strip construction, and

of the strip by Fig. 7 is a greatly enlarged cross-section showing several layers of a third modied strip construction.

Referring to Fig. 1, l is the rotatable axle which carries the sleeve 2 secured thereto by means of the set screw 3, the xedfiange 4 and the adjustable flange 5 which is positioned by the nut 6 screw-threaded on the sleeve 2. The parts l to 6 constitute a spool. for mounting the abrasive wheels.

The abrasive wheels are formed by winding the abrasive strip around a Cylindrical core or tube 'l until the desired size of wheel is produced. As stated above, the abrasive strip is capable of being used as such like any ordinary piece of sandpaper or it may be mounted in a plurality of superposedflat layers to. form a pad or it can be wound, preferably upon a flexible belt support, to form an abrasive belt but since suchV uses of the strip are entirely analogous to the similar uses of ordinary sandpaper they are not illustrated.

Referring to Fig. 2, 8 is the fiexible support, e. g. paper, for the abrasive, 9 is the layer of abrasive grains, lll is the envelope in the form of a strip which extends across the non-abrasive surface of the support 8 and has its free edges folded over the abrasive surface andl brought together or nearly so near the middle of the strip, and Il is a protecting strip which lies between the abrasive surface and the envelope. In making the strip, adhesive is applied as indicated by the heavy line I2 between the non-abrasive surface of the abrasive supporting strip 8 and the inside surface of the contiguous portion o'f the envelope l0. When the strip is wound to form a Wheel the back of the strip, surface of that portion of the envelope I0 which extends across the non-abrasive surface of the support 8 isv glued to the core or tube I as indicated by the heavy line I3, then the back surface of theV second turn or layer is glued tothe front of the iirst layer as indicated by the heavy` line I4, the third layer is secured to the second layer and so on. In use the inturned edges. of

the envelope l0 are torn 01T as shown at I5'and the protecting strip ll removed to expose the abrasive surface. When the abrasive surface of the. outermostlayer or turn of the wheel becomes worn it is removed, exposing the abrasive sur# face ofthe second layer and so on until the wheel has been consumed. The protecting strip Il serves principally to prevent adhesive which is applied to secure the back of each layerA ofthe strip to the front of the' preceding layer from flowing between theV inturned edges of the that is the outside envelope I and depositing upon the abrasive surface. If the adhesive is carefully handled or for instance applied not all over the back of the strip but merely in stripes positioned laterally of the open space between the inturned edges of the envelope Il) so that the danger of adhesive enteringbetween the edges of the envelope is eliminated, then the protecting strip II may be omitted.

In the embodiment illustrated in Fig. 2, the inturned edges of the envelope I0 are tightly or snugly folded around the edges of the sandpaper and there is relatively little expansion or separation of the layers of the strip when subjected to centrifugal force, i. e. when the wheel is rotated although, as will be apparent, some separation of the layers of the strip due to centrifugal force will occur.

In the embodiment illustrated in Fig. 3 the parts are identical withr those in Fig. 2 but the inturned edges of the envelope Ill are not tightly folded around the edges of the sandpaper and when the wheel is rotated the resulting centrifugal force causes a separation of the layers and produces the open spaces I6, I6. Then when .pressure is applied to the surface of the roll by an object I1 being sanded as illustrated in Fig. 4 the open spaces I6, I6 are wholly or partly closed and the edges I8, I8 of the envelope bulge outwardly. This compressibility of the wheel gives it a soft, smooth action on the object being sanded, a well-known desirable characteristic of abrasive wheels. v

In Figs. 5, 6 and 7 for brevity, I have illustrated only the partly compressed structures as in Fig; 4 but it is to be understood that each of the structures illustrated in Figs. 5, 6 and 7 may be constructed tightly as in Fig. 2 or loosely as in Fig. 3.

In the modification illustrated in Fig. 5, I is the wall of the supporting core or tube, 8 is the abrasive support, 9 is the abrasive layer and II is the protecting strip as in Figs. 2, 3 and 4. In place of the envelope I9 of Figs. 2, 3, and 4, I have substituted the two relatively narrow strips I9, I9 of flexible material such as paper, each of which has one edge adhesively secured to the nonabrasive surface of the support 8 by the glue line 2U and its other edge secured to the next strip at the glue line 2|. Thus it will be seen that a large proportion of the material of the envelope I0 is saved and at the same time the wheel formed of the strip is rendered more compressible and soft by the open spaces 22 left by the absence of the omitted portions of the envelope I9. In this modification, illustrated in Fig. 5, as Well as in all of the other embodiments illustrated in Figs. 2, 3, 4, 6 and '7, the protecting strip II may be omitted.

In the modification illustrated in Fig. 6 the envelope In of Figs. 2, 3 and 4 and the strips I9 of Fig. are omitted and replaced in part by the non-abrasive integral edge portions 23 of the abrasive support 8. This modification, as illustrated, includes the optional protective strip II and the non-abrasive edge portions of the abrasive support may be either tightly folded as in Fig. 2 or loosely folded as in Fig. 3 to leave the open spaces 24 permitting compression of the wheel and partial or complete closing of the spaces with a corresponding bulging of the edges 25, 25 under the pressure of the article being sanded.

The modification illustrated in Fig. 7 is further simplified, with a further saving of the flexible sheet material, e. g. paper, by providing the abrasive support 8 with integral non-abrasive edge portions 26 which are only wide enough to make the connection between successive layers of the abrasive strip. In this modication also the protecting strip II may be omitted; the successive layers of the abrasive strip are adhesively secured together by the application of adhesive exclusively to non-abrasive surfaces, the strips may be compactly formed as in Fig. 2 or loosely formed as in Fig. 3 to provide open spaces for the compression of the strip, the compression may occur with expansion outwardly, as in Fig. 4, of the connecting portion of the flexible sheet material and successive layers of the abrasive strip may be torn off when worn to expose a fresh abrasive surface by tearing this connecting portion of the flexible sheet material.

I claim:

1. An abrasive tool comprising a plurality of superposed layers, said layers each comprising a flexible support having on at least a portion of one surface thereof an adhesively attached coating of abrasive material, a exible attaching strip extending at least from adjacent the edge of the abrasive coated portion of said support around the edge of said abrasive coating and over at least a part of the free surface thereof and adhesively attached to the back of the next superposed layer, the width of that portion of the attaching strip extending around the edge of the abrasive coating between the edge of the abrasive coated portion of the support of one layer and the back of the next superposed layer being greater than the thickness of the abrasive coating and permitting separation between the free surface of said abrasive coating and the back of the next superposedlayer.

2. Abrasive tool as defined in claim 1 in which the attaching strip is integral with the flexible support.

3. Abrasive tool as defined in claim 1 in which the attaching strip is an integral edge portion of a strip which is adhesively attached to the non-abrasive surface of the abrasive coated portion of the flexible support.

4. Abrasive tool as defined in claim 1 in which attaching strips at the opposite edges of the abrasive coated portion of the flexible support together extend substantially completely across the free surface of the abrasive coating.

5. Abrasive tool as defined in claim 1 in which the attaching strips at the opposite edges of the abrasive coated portion of the exible support extend only a small fraction of the distance y across the free surface of the abrasive coating.

6. Abrasive tool as dei-ined in claim 1 in which the attaching strips at the opposite edges of the abrasive coated portion of the exible support are integral with the flexible support and together extend substantially across the free surface of the abrasive coating.

7. Abrasive tool as defined in claim 1 in which the attaching strips at the opposite edges of the abrasive coated portion of the flexible support are the edge portions of a strip which extends com-l pletely across the back of. the exible strip and is adhesively attached thereto and said edge portions together extend substantially completely across the front of the abrasive coating.

8. Abrasive tool as defined in claim 1 in which the attaching strips at the opposite edges of 'the abrasive coated portion of the flexible support are edge portions of strips which extendonly a small fraction of the distance across the back of the non-abrasive surface of the abrasive y,coated portion of the flexible support and are adhesively REFERENCES CITED attached thereto and said edge portions extend only a small fraction of the distance across the lrghf {Gtgwgeerences are of record in the free surface of the abrasive coating. p

5 UNITED STATES PATENTS GEORGE W. ALLRED. Number Name Date 2,362,739 Allred Nov. 14, 1944 2,422,876 Allred June 24, 1947 

